6-Piperidino-dibenz[d,g][1,3,6,2]dioxathiophosphocine

ABSTRACT

Compounds of the formula I ##STR1## wherein R 1  is hydrogen, C 1  -C 18  alkyl, C 5  -C 12  cycloalkyl, phenyl or C 7  -C 9  phenylalkyl and R 2  is hydrogen or C 1  -C 18  alkyl, or, if R 1  is hydrogen, R 2  is a divalent 1,1,3,3-tetramethylpropylene radical fused in the 2-position and 3-position or the 9-position and 10-position, and X is sulfur or a group --CH(R) 3  --, in which R 3  is hydrogen or a radical of the formula II --CH(R 4 )--CH(R 5 )SR 6 , and each of R 4  and R 5  independently is hydrogen or C 1  -C 6  alkyl and R 6  is C 1  -C 20  alkyl, while the alkyl group can be interrupted by one or more sulfur atoms, and A is a primary or secondary aliphatic or alicyclic, aromatic or araliphatic amine which contains substituents of the same type or mixed substituents, or a heterocyclic amine or a hydrazine derivative. These compounds are useful stabilizers for organic material.

This is a divisional of application Ser. No. 146,974, filed on May 5, 1980, now U.S. Pat. No. 4,322,527, issued on Mar. 30, 1982.

The present invention relates to novel N-substituted 6-amino-dibenz[d,g][1,3,2]dioxaphosphocines, a process for their manufacture, their use as stabilisers for organic material, and the organic material stabilised with these compounds.

Phosphorous acid triesters are known as stabilisers. Thus, for example, substituted 6-phenoxy-12H-dibenz[d,g][1,3,2]dioxaphosphocines are described in U.S. Pat. No. 3,297,631. However, these compounds do not satisfy in every respect the exacting demands which a stabiliser should meet, in particular in respect of storage life, water adsorption, susceptibility to hydrolysis, processing stability, colour properties, volatility, migration properties, compatibility, and improvement in light stabilisation.

It is the object of this invention to provide stabilisers which do not have these disadvantages or which have them to a lesser extent.

Accordingly, the present invention relates to N-substituted 6-amino-dibenz[d,g][1,3,2]dioxaphosphocines of the formula I ##STR2## wherein R₁ is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl, phenyl or C₇ -C₉ phenylalkyl and R₂ is hydrogen or C₁ -C₁₈ alkyl, or, if R₁ is hydrogen, R₂ is a divalent 1,1,3,3-tetramethylpropylene radical fused in the 2- and 3-position or the 9- and 10-position, and X is sulfur or a --CH(R)₃ group, in which R₃ is hydrogen or a radical of the formula II --CH(R₄)--CH(R₅)SR₆, and each of R₄ and R₅ independently is hydrogen or C₁ -C₆ alkyl and R₆ is C₁ -C₂₀ alkyl, while the alkyl group can be interrupted by one or more sulfur atoms, and A is a primary or secondary aliphatic, alicyclic, aromatic or araliphatic amine which contains substituents of the same type or mixed substituents, or a heterocyclic amine or a hydrazine derivative.

R₁ and R₂ as C₁ -C₁₈ alkyl are in particular straight-chain or branched alkyl of 1 to 8 carbon atoms, for example methyl, ethyl, n-propyl, isopropyl, sec-butyl, tert-butyl, tert-pentyl, n-octyl, 2-ethylhexyl or 1,1,3,3-tetramethylbutyl. R₁ is preferably α-branched. In particularly preferred compounds, R₁ and R₂ are identical and are e.g. tert-butyl.

R₁ as C₅ -C₁₂ cycloalkyl can be cyclopentyl, cycloheptyl, cyclooctyl, cyclododecyl and especially cyclohexyl.

R₁ as C₇ -C₉ phenylalkyl is e.g. benzyl, 2-phenylethyl or α,α-dimethylbenzyl.

The radicals R₂ can be in the 1- and 11-position but are preferably in the 2- and 10-position.

X can be sulfur or a --CHR₃ group, in which R₃ is preferably hydrogen or a group of the formula II. R₄ and R₅ as C₁ -C₆ alkyl in formula II are e.g. methyl, ethyl, isopropyl, n-butyl or n-hexyl, but are preferably hydrogen. R₆ as C₁ -C₂₀ alkyl is e.g. methyl, ethyl, n-propyl, sec-butyl, n-octyl, n-octadecyl or n-eicosyl and can be interrupted by one or more sulfur atoms. It is preferred, however, that there are at least two carbon atoms between two sulfur atoms. Examples are --(CH₂)₃ --S--(CH₂)₂ --CH₃, --CH₂ CH₂ --S--(CH₂)₄ --S--CH₂ CH₃ or --CH₂ CH₂ --S--CH₃. X is preferably --CH₂ --.

A is a primary or secondary amine which contains substituents of the same type or mixed substituents and which can contain up to six primary and/or secondary amino groups. Preferred compounds are those in which all of the primary or secondary amine nitrogens present in the molecule are substituted by a group of the formula III ##STR3## wherein the symbols R₁, R₂ and X are as defined above.

Especially interesting amines are secondary amines, and in particular branched amines.

Preferred amines A are, therefore, those of the formula IV ##STR4## wherein R₇ is hydrogen, C₁ -C₂₂ alkyl, C₂ -C₂₁ oxa- or thiaalkyl, C₃ -C₁₈ alkenyl, C₃ -C₁₈ alkynyl, C₂ -C₆ hydroxyalkyl, C₃ -C₂₄ alkoxycarbonylalkyl, C₅ -C₁₂ cycloalkyl, C₆ -C₁₄ aryl, C₇ -C₁₅ alkaryl, C₇ -C₁₅ aralkyl, a substituted or unsubstituted C₅ -C₁₇ piperidin-4-yl group or a group of the formula III, in which R₁, R₂ and X are as defined above, and R₈ is C₁ -C₂₂ alkyl, C₂ -C₂₁ oxa- or thiaalkyl, C₃ -C₁₈ alkenyl, C₃ -C₁₈ alkynyl, C₂ -C₆ hydroxyalkyl, C₃ -C₂₄ alkoxycarbonylalkyl, C₅ -C₁₂ cycloalkyl, C₆ -C₁₄ aryl, C₇ -C₁₅ alkaryl, C₇ -C₁₅ aralkyl, a substituted or unsubstituted C₅ -C.sub. 17 piperidin-4- or -1-yl group or a group of the formula ##STR5## wherein R₇ is as defined above and n is 0 or 1 and R₉ is C₂ -C₂₂ alkylene which can be interrupted by one or two oxygen or sulfur atoms, or is C₄ -C₂₂ alkenylene, C₄ -C₂₂ alkynylene, C₅ -C₉ cycloalkylene or a group of the formula VII ##STR6## in which R₁₀ is --O--, --S-- or --(R₁₁)C(R₁₂)--, in which each of R₁₁ and R₁₂ independently is hydrogen or C₁ -C₈ alkyl, or R₁₁ and R₁₂ together with the carbon atom to which they are attached form C₅ -C₁₂ cycloalkyl; and R₉ is also phenylene, biphenylene or a group of the formula VIII ##STR7## in which R₁₀ is as defined above, and each of r, t and u independently is 2, 3, 4, 5 or 6 and m is 0, 1, 2 or 3, and Q is a group of the formula III, in which R₁, R₂ and X are as defined above; or R₇ and R₈ together with the nitrogen atom to which they are attached are substituted pyrrolidine, oxazolidine, piperidine or morpholine, or R₇ and R₈ together form the radical --CH₂ --CH₂ --N(Q)--CH₂ --CH₂ --, in which Q is as defined above.

R₇ and R₈ as C₁ -C₂₂ alkyl can be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, isohexyl, n-octyl, 1,1,3,3-tetramethylbutyl, n-nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl or docosyl. Alkyl groups R₇ and R₈ preferably contain 1 to 18 carbon atoms. In particular, R₇ and R₈ contain 1 to 12 and 1 to 4 carbon atoms respectively. R₇ and R₈ as oxa- and thiaalkyl of 2 to 21, especially 4 to 21, carbon atoms, are preferably alkoxy- or alkylthiopropyl, such as butoxypropyl, dodecylthiopropyl, octyloxypropyl or octadecyloxypropyl.

R₇ and R₈ as C₃ -C₁₈ alkenyl are e.g. allyl, methallyl, n-hex-3-enyl, n-oct-4-enyl or n-undec-10-enyl. Preferred radicals are allyl and methallyl, and especially allyl.

R₇ and R₈ as C₃ -C₁₈ alkynyl are e.g. propargyl, n-but-1-ynyl, n-but-2-ynyl or n-hex-1-ynyl. Preferred alkynyl groups are those containing 3 or 4 carbon atoms and especially propargyl.

R₇ and R₈ as hydroxyalkyl containing 1 to 6 carbon atoms can be 2-hydroxypropyl, 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl or 6-hydroxyhexyl.

R₇ and R₈ as C₃ -C₂₄ alkoxycarbonylalkyl, preferably C₃ -C₂₄ alkoxycarbonylmethyl or -ethyl, and in particular C₃ -C₁₄ alkoxycarbonylmethyl or C₃ -C₁₅ alkoxycarbonylethyl, can be e.g. methoxycarbonylmethyl, ethoxycarbonylmethyl, methoxycarbonylethyl, octoxycarbonylmethyl, octoxycarbonylbutyl, dodecyloxycarbonylethyl or octadecyloxycarbonylethyl.

R₇ and R₈ as cycloalkyl of 5 to 12, preferably 5 to 8 and most preferably 6, carbon atoms, are e.g. cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl.

R₇ and R₈ as C₆ -C₁₄ aryl are e.g. phenyl, α-naphthyl, β-naphthyl or phenanthryl. Phenyl groups are preferred.

R₇ and R₈ as aralkyl containing 7 to 15 carbon atoms are e.g. benzyl, α-phenylethyl, α,α-dimethylbenzyl or 2-phenylethyl, preferably benzyl.

R₇ and R₈ as C₇ -C₁₅ alkaryl groups can be e.g. tolyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,4,6-triisopropylphenyl or 4-tert-butylphenyl.

If R₇ is a group of the formula III, this group is preferably substituted in the same way as the dibenz[d,g][1,3,2]dioxaphosphocin-6-yl radical already present in the molecule.

If R₇ and R₈ together with the nitrogen atom to which they are attached form a pyrrolidine, oxazolidine or morpholine ring, these heterocyclic rings can be substituted by up to five methyl or ethyl groups. These ring systems are preferably unsubstituted.

R₇ and R₈ as C₅ -C₁₇ piperidin-4-yl groups can be e.g. unsubstituted piperidin-4-yl, or the piperidine can be substituted by up to 5 alkyl groups, preferably by methyl or ethyl groups. Preferred positions for substitution are the 2-position and the 6-position in the piperidine ring. The groups can also be 3,3,5-trimethyl-8-ethoxy-bicyclo[4.4.0]dec-2-yl.

R₇ and R₈ can therefore form piperidin-4-yl or piperidin-1-yl groups of the following constitution: ##STR8## in which R₁₃ is hydrogen or methyl and R₁₄ is hydrogen, oxyl, C₁ -C₁₈ alkyl, C₃ -C₈ alkenyl, C₃ -C₆ alkynyl, C₇ -C₁₂ aralkyl, C₂ -C₂₁ alkoxyalkyl, an aliphatic acyl group containing 1 to 4 carbon atoms or a --CH₂ COOR₁₅ group, in which R₁₅ is C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, phenyl, C₇ -C₈ aralkyl or cyclohexyl.

The most preferred piperidin-4-yl radicals are those in which R₁₃ is hydrogen and R₁₄ is hydrogen, methyl or acetyl. R₁₃ is preferably hydrogen.

R₁₄ as C₁ -C₁₈ alkyl is e.g. methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl, n-dodecyl or octadecyl. Preferred alkyl groups are those containing 1 to 12 carbon atoms, and also those containing 1 to 8 carbon atoms, and especially those containing 1 to 4 carbon atoms, in particular methyl.

R₁₄ as C₃ -C₈ alkenyl is e.g. allyl, 3-methyl-2-butenyl, 2-butenyl, 2-hexenyl or 2-octenyl, especially allyl.

R₁₄ as C₃ -C₆ alkynyl is e.g. propargyl.

R₁₄ as C₇ -C₁₂ aralkyl is e.g. benzyl, β-phenylethyl or 4-tert-butylbenzyl, preferably benzyl.

Where R₁₄ is C₂ -C₂₁ alkoxyalkyl, the alkyl moiety can contain 1 to 3 carbon atoms and the alkoxy moiety can contain 1 to 18 carbon atoms, for example methoxymethyl, ethoxymethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-n-butoxyethyl, 3-n-butoxypropyl, 2-octoxyethyl or 2-octadecyloxyethyl: Preferred compounds are those in which R₁₄ is an alkoxyalkyl group containing 2 to 6 carbon atoms.

As an aliphatic acyl group having 1 to 4 carbon atoms, R₁₄ is e.g. formyl, acetyl, acryloyl or crotonyl, especially acetyl.

If R₁₄ is the --CH₂ COOR₁₅ group, R₁₅ as C₁ -C₁₂ alkyl is e.g. methyl, ethyl, isopropyl, n-butyl, isobutyl, tert-butyl, isopentyl, n-octyl or n-dodecyl. R₁₅ is preferably C₁ -C₄ alkyl. R₁₅ as C₃ -C₈ alkenyl is e.g. allyl, 2-butenyl or 2-hexenyl. R₁₅ as C₇ -C₈ aralkyl is e.g. benzyl or α-phenylethyl.

n can be 0 or preferably 1.

R₉ as C₂ -C₂₂ alkylene, preferably C₂ -C₉ alkylene and in particular C₂ -C₆ alkylene, can be e.g. dimethylene, trimethylene, tetramethylene, hexamethylene, octamethylene, nonamethylene, 2,2,4-trimethylhexamethylene, decamethylene, dodecamethylene, octadecamethylene or docosamethylene. If the alkylene groups are interrupted by --O-- or --S--, these groups can be 2-thia-1,3-propylene, 3-thia-1,5-pentylene, 4-oxaheptamethylene or 3,6-dioxa-1,8-octylene.

R₉ as C₄ -C₂₂ alkylene or alkynylene is e.g. 2-butenylene-1,4; 2-butylene-1,4:, 2,4-hexadiynylene-1,6 or propenylene-1,3.

R₉ as C₅ -C₉ cycloalkylene is e.g. 1,2-cyclopentylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, 1,4-cycloheptylene or 1,2-cyclononylene. As cycloalkylene R₉ preferably contains 6 carbon atoms.

R₁₁ and R₁₂ as C₁ -C₈ alkyl are e.g. ethyl, n-propyl, isopropyl, n-butyl, n-phenyl, n-hexyl or n-octyl; it is preferred, however, that alkyl groups R₁₁ and R₁₂ are methyl.

R₁₁ and R₁₂ together with the carbon atom to which they are attached can also form C₅ -C₁₂ cycloalkyl, preferably cyclohexyl. The cycloalkyl group can be cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl or cyclododecyl.

Each of r, t and u independently is 2, 3, 4, 5 or 6, but is preferably the same and most preferably is 2 or 3.

m can be 0, 1, 2 or 3. Preferably m is 0 or 1 and is most preferably 0.

If the compounds contain radicals Q, the latter preferably have the same substituents as the other dibenz[d,g][1,3,2]dioxaphosphocin-6-yl radicals present in the molecule.

Preferred compounds of the formula I are those in which R₁ and R₂ are C₁ -C₁₈ alkyl, and R₂ is also hydrogen, and X is sulfur or --CH₂ -- and A is a group --N(R₇)R₈, in which R₇ is hydrogen, C₁ -C₁₈ alkyl, C₃ -C₄ alkenyl, C₃ -C₄ alkynyl, C₃ -C₂₄ alkoxycarbonylmethyl or -ethyl, C₅ -C₁₂ cycloalkyl, phenyl, benzyl, C₇ -C₁₅ alkaryl, a substituted or unsubstituted C₅ -C₁₇ piperidin-4-yl group or a group of the formula III, in which R₁, R₂ and X are as defined above, and R₈ is C₁ -C₁₈ alkyl, C₃ -C₄ alkenyl, C₃ -C₄ alkynyl, C₃ -C₂₄ alkoxycarbonylmethyl or -ethyl, C₅ -C₁₂ cycloalkyl, phenyl, benzyl, C₇ -C₁₅ alkaryl, a substituted or unsubstituted C₅ - C₁₇ piperidin-4-yl group or a group of the formula V or VI, in which R₇ is as defined above and n is 0 or 1 and R₉ is C₂ -C₉ alkylene which can be interrupted by one or two oxygen or sulfur atoms, or is cyclohexylene or a group of the formula VII, in which R₁₀ is --O--, --S-- or --(R₁₁)C(R₁₂)--, in which each of R₁₁ and R₁₂ independently is hydrogen or methyl, or R₁₁ and R₁₂ together with the carbon atom to which they are attached form cyclohexylene, and r, t and u are 2 or 3 and m is 0 or 1 and Q is a group of the formula III, in which R₁, R₂ and X are as defined above, or R₇ and R₈ together with the nitrogen atom to which they are attached form a pyrrolidine, oxazolidine, piperidine or morpholine ring, or R₇ and R₈ together are the radical --CH₂ CH₂ --N(Q)--CH₂ CH₂ --, in which Q is as defined above.

Interesting compounds of the formula I are those in which R₁ is α-branched C₃ -C₈ alkyl and R₂ is C₁ -C₈ alkyl and X is sulfur or --CH₂ -- and A is a group --N(R₇)R₈ (IV), in which R₇ is hydrogen, C₁ -C₁₈ alkyl, allyl, propargyl, C₃ -C₁₄ alkoxycarbonylmethyl, C₃ -C₁₅ alkoxycarbonylethyl or C₅ -C₈ cycloalkyl and R₈ is C₁ -C₄ alkyl, allyl, propargyl, C₃ -C₁₄ alkoxycarbonylmethyl, C₃ -C₁₅ alkoxycarbonylmethyl, C₅ -C₈ cycloalkyl or a group of the formula V or VI, in which R₇ is as defined above and n is 1 and R₉ is C₂ -C₆ alkylene and r, t and u are 2 or 3 and m is 0 and Q is a group of the formula III, in which R.sub. 1, R₂ and X are as defined above, or R₇ and R₈ together with the carbon atom to which they are attached form a piperidine or morpholine ring, or R₇ and R₈ together are the radical --CH₂ CH₂ --N(Q)--CH₂ CH₂ --, in which Q is as defined above.

Particularly preferred compounds of the formula I are those in which R₁ and R₂ are α-branched C₃ -C₈ alkyl and X is sulfur or --CH₂ -- and A is a group --N(R₇)R₈ (IV), in which R₇ is hydrogen, C₁ -C₁₂ alkyl or cyclohexyl and R₈ is C₁ -C₄ alkyl, cyclohexyl or a group of the formula V, in which R₇ is as defined above and Q is a group of the formula III, in which R₁, R₂ and X are as defined above, and n is 1 and R₉ is C₂ -C₆ alkylene, or R₇ and R₈ together with the carbon atom to which they are attached form a piperidine or morpholine ring, or R₇ and R₈ together are the radical --CH₂ CH₂ --N(Q)--CH₂ CH₂ --, in which Q is as defined above.

Examples of compounds of the formula I are:

(1) 6-(di-n-octylamino)-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine,

(2) 6-(2'-aza-3',3',5'-trimethyl-8'-ethoxy-bicyclo[4.4.0]dec-2'-yl)-2,4,8,10-tetra-tert-butyl-dibenz[d,g][1,3,6,2]dioxa-thiaphosphocine,

(3) 6-(N-2',6'-dimethylphenyl-N-cyclohexylamino)-2,10-dimethyl-4,8-di-tert-butyl-dibenz[d,g][1,3,6,2]dioxathiaphosphocine,

(4) 6-(dicyclohexylamino)-2,4,8,10-tetra-tertbutyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine,

(5) 6-(N,N-dimethylamino)-2,4,8,10-tetra-(1',1',3',3'-tetramethylbutyl)-dibenz[d,g][1,3,6,2]dioxa-thiaphosphocine,

(6) 6-morpholino-2,4,8,10-tetramethyl-12H-dibenz[d,g][1,3,2]dioxa-phosphocine,

(7) 6-(di-n-butylamino)-2,10-dimethyl-4,8-di-tertbutyl-12-(2'-dodecylthio-propyl)-12H-dibenz[d,g][1,3,2]dioxaphosphocine,

(8) 6-[di-(hydroxyethyl)-amino]2,10-di-(1',1',3',3'-tetramethylbutyl)-dibenz[d,g][1,3,6]dioxathiaphosphocine,

(9) 6-(2',4'-dimethylanilino)-2,4,8,10-tetra-tertbutyl-dibenz[d,g][1,3,6,2]dioxa-thiaphosphocine,

(10) 6-[p-(phenylamino)-anilino]-2,10-dimethyl-4,8-di-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine,

(11) (Z--CH₂ CH₂ O)₂ N--Z (*)

(12) (CH₃ CH₂ --N(Z)--CH₂ CH₂)₂ --N--Z (*)

(13) CH₃ --(CH₂)₃ --CH(C₂ H₅)--CH₂ --N--(Z)₂ (*)

(14) ##STR9##

Compound 14 exemplifies a compound in which R₂ forms a 1,1,3,3-tetramethylpropylene radical fused in the 2- and 3-position or 10- and 11-position.

The phosphites of the formula I can be obtained by methods known per se, especially by amidation or transamidation processes, for example by reacting a phosphorous acid diester of the formula X ##STR10## in which Y is a reactive group and R₁, R₂ and X are as defined above, with an amine R₁₆ -A, in particular with an amine of the formula

    R.sub.16 N(R.sub.7)R.sub.8                                 (XI)

in which R₁₆ is hydrogen or a Na, Li or K atom and A, R₇ and R₈ are as defined above.

A reactive group Y is e.g. halogen, especially chlorine, or alkoxy, phenoxy, or a primary or secondary amino group.

An alternative method of obtaining compounds of the formula I comprises reacting a phosphorus amide of the formula

    (Hal).sub.2 --P--A                                         (XII)

in which Hal is a halogen atom, especially chlorine, and Z is as defined above, with a diphenol of the formula ##STR11## in which R₁, R₂ and X are as defined above.

Both types of reaction can be carried out in a manner known per se, for example in the temperature range from -5° C. to 80° C., or by heating, preferably to a temperature above about 80° C., for example in the range from 80°-170° C. The reaction can be carried out without a solvent or in the presence of an inert solvent, such as an aprotic solvent, for example ligroin, toluene, xylene, hexane, cyclohexane, dimethylformamide, dimethylacetamide, sulfolane, acetonitrile, dioxane, di-n-butyl ether 1,2-dichloroethane, dimethyl sulfoxide, ethyl acetate, methyl ethyl ketone, nitrobenzene, nitromethane, tetrahydrofurane chloroform or trichloroethylene. If X is halogen, the reaction is advantageously carried out in the presence of a base, such as sodium carbonate or an amine, for example triethylamine, pyridine or N,N-dimethylaniline. However, it is entirely possible to carry out the reaction with an excess of the amine of the formula XI, in which case this amine acts as acid acceptor. Amine bases employed in excess can at the same time act as solvents.

The starting materials of the formulae X, XI, XII and XIII are known, or, if they are novel, can be prepared analogously to known compounds. The phosphites of the formula X can be prepared from the corresponding diphenol compounds of the formula XIII and PY₃, in which Y is as defined above. Diphenol compounds of the formula XIII in which --X-- is a --CH₂ -- group can be prepared by methods analogous to those described in U.S. Pat. No. 4,055,539.

In the practice of the present invention, the compounds of the formula I can be used as stabilisers for protecting plastics and elastomers against damage caused by the action of oxygen, light and heat. Examples of such plastics are the polymers listed on pages 12-14 of German Offenlegungsschrift 2 456 864.

Examples of suitable substrates are:

1. Polymers which are derived from mono-unsaturated hydrocarbons, such as polyolefins, for example low density and high density polyethylene which may or may not be crosslinked, polypropylene, polyisobutylene, polymethylbut-1-ene and polymethylpent-1-ene.

2. Mixtures of the homopolymers listed under 1, for example mixtures of polypropylene and polyethylene, of polypropylene and polybut-1-ene and of polypropylene and polyisobutylene.

3. Copolymers of the monomers on which the homopolymers listed under 1 are based, such as ethylene/propylene copolymers, propylene/but-1-ene copolymers, propylene/isobutylene copolymers and ethylene/but-1-ene copolymers, and also terpolymers of ethylene and propylene with a diene, for example hexadiene, dicyclopentadiene or ethylidenenorbornene.

4. Polystyrene and its copolymers, such as SAN, ABS, IPS, ASA and EP modified styrene copolymers.

5. Polyamides.

6. Linear polyesters.

7. Polyurethanes.

8. Polycarbonates.

9. Elastomers, such as polybutadiene, SBR, polyisoprene, polychloroprene and nitrile rubber.

10. Thermoplastic elastomers, such as SBS, SIS and S-EP-S.

11. Polyvinyl chloride and the like.

12. Synthetic- and mineral-based lubricating oils.

The present invention also relates to a method of stabilising polymers against degradation caused by heat and oxidation during production, isolation, processing and use, which method comprises incorporating at least one compound of the formula I in the polymer.

The compounds of the formula I are incorporated in the substrates in a concentration of 0.005 to 5% by weight, based on the material to be stabilised.

Preferably, 0.01 to 1.0, and most preferably 0.02 to 0.5%, by weight of the compounds, based on the material to be stabilised, is incorporated into the latter. Incorporation can be effected, for example, by blending in at least one of the compounds of the formula I and, if desired, further additives, by the methods conventionally employed in the art, before or during shaping, or by applying the dissolved or dispersed compounds to the polymer, with subsequent evaporation of the solvent if desired.

The novel compounds can also be added to the plastics to be stabilised in the form of a master batch which contains these compounds, for example in a concentration of 2.5 to 25% by weight.

In the case of crosslinked polyethylene, the compounds are added before crosslinking.

The invention therefore also relates to the plastics which are stabilised by the addition of 0.01 to 5% by weight of a compound of the formula I and which, if desired, can also contain further additives. The plastics stabilised in this way can be employed in very diverse forms, for example in the form of films, fibres, ribbons or profiles or as binders for lacquers, adhesives or putties.

Examples of further additives together with which the stabilisers can be employed are: antioxidants, UV absorbers and light stabilisers, such as 2-(2'-hydroxyphenyl)-benztriazoles, 2,4-bis-(2'-hydroxyphenyl)-6-alkyl-s-triazines, 2-hydroxybenzophenones, 1,3-bis-(2'-hydroxybenzoyl)-benzenes, esters of substituted or unsubstituted benzoic acids and acrylates, and furthermore nickel compounds, sterically hindered amines, oxalic acid diamides, metal deactivators, phosphites, compounds which destroy peroxide, polyamide stabilisers, basic costabilisers, nucleating agents or other additives, for example plasticisers, lubricants, emulsifiers, fillers, carbon black, asbestos, kaolin, talc, glass fibres, pigments, fluorescent whitening agents, flame retardants and antistatic agents.

The following examples illustrate the invention in more detail.

EXAMPLE

17.9 g of 2,2'-thio-bis-(4-methyl-6-tertbutyl)-phenol, 5 ml of phosphorus trichloride and 30 ml of xylene are heated slowly to 90°-100° C. After a reaction time of five hours, the mixture is cooled to room temperature. Then 5.5 g of triethylamine and 4.5 g of piperidine are added and the mixture is kept at reflux temperature for 20 hours. The mixture is filtered and the solvent is stripped off in vacuo, affording ##STR12##6-morpholino-2,10-dimethyl-4,8-di-tert-butyl-dibenz[d,g][1,3,6,2]dioxa-thia-phosphocine with a melting point of 200° C. (stabiliser 1).

The following stabilisers are obtained under the same reaction conditions using methylene-bis-phenols:

stabiliser 2: 6-di-n-butylamino-2,4,8,10-tetra-(1',1',3',3'-tetramethylbutyl)-12H-dibenz[d,g][1,3,2]-dioxaphosphocine (m.p. 113° C.)

stabiliser 3: 6-morpholino-2,4,8,10-tetra-(1',1',3',3'-tetramethylbutyl)-12H-dibenz[d,g][1,3,2]-dioxaphosphocine (m.p. 146° C.)

stabiliser 4: 6-morpholino-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine (m.p. 200° C.)

stabiliser 5: N,N'-dimethyl-N,N'-di-(2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocin-6-yl)-ethylenediamine (m.p. 260° C.)

stabiliser 6: 6-di-n-butylamino-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine (m.p. 100°-105° C.)

stabiliser 7: 6-morpholino-2,10-dimethyl-4,8-di-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine (m.p. 160° C.)

stabiliser 8: 6-(2,2,6,6-tetramethyl-piperidine-1-yl)-2,4,8,10-tetramethyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine (m.p. 198° C.)

stabiliser 9: 6-di-n-butylamino-2,10-dimethyl-4,8-di-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine (m.p. 118°-120° C.)

stabiliser 10: 6-(2,2,6,6-tetramethyl-piperidine-1-yl)-2,10-dimethyl-4,8-di-tert-butyl-12H-dibenz[d,g][1,3,2]dioxaphosphocine (m.p. 188° C.).

EXAMPLE 11

100 Parts of high molecular weight polypropylene powder (Lupolen 5260 Z, available from BASF) are mixed with 0.05 part of pentaerythritol tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and the compounds listed in Table I, and the mixture is kneaded in a Brabender plastograph at 220° C. and 50 rpm. During this time the kneading resistance is continuously recorded as torque. In the course of the kneading procedure, the polymer begins to crosslink after remaining constant for some considerable time. The crosslinking can be observed from the rapid increase in the torque. The effectiveness of the stabiliser is expressed in a prolongation of the constancy.

                  TABLE I                                                          ______________________________________                                                          Time in minutes until                                         Stabiliser       change in the torque                                          ______________________________________                                         0.1    part of compound 1                                                                           15'                                                       0.1    part of compound 2                                                                           9'                                                        0.1    part of compound 3                                                                            9.5'                                                     0.1    part of compound 4                                                                           16.5'                                                     0.05   part of compound 5                                                                           9'                                                        0.1    part of compound 6                                                                            7.0'                                                     0.1    part of compound 7                                                                           14.5'                                                     0.1    part of compound 8                                                                           14.0'                                                     0.05   part of compound 9                                                                            8.0'                                                     0.1    part of compound 10                                                                          11.5'                                                     ______________________________________                                    

EXAMPLE 12

100 Parts of polypropylene powder (Propathene HF 22, available from ICI) are mixed with 0.1 part of calcium stearate, compound 7 in the amounts indicated in Table II, and pentaerythritol tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (0.05%).

The mixtures are extruded 5 times in succession in a single-screw extruder at a maximum temperature of 260° C. and 3 times in succession in the same extruder at 280° C., each time at 100 rpm. The melt index of the polymer is measured after the 1st, 3rd and 5th extrusion at 260° C. and after the 1st and 3rd extrusion at 280° C. The load is 2160 g, the temperature 230° C. and the measurable variable is g/10 min.

                  TABLE II                                                         ______________________________________                                                    melt index after several extrusions                                            at 260° C.                                                                            at 280° C.                                     Stabiliser   1.       3.    5.     1.  3.                                      ______________________________________                                         without      6.3      8.9   15.0   7.1 21.4                                    with 0.025 part of                                                             compound 7   4.7      6.7   9.1    6.8 14.8                                    with 0.05 part of                                                              compound 7   3.8      4.8   6.3    4.9 8.6                                     ______________________________________                                     

What is claimed is:
 1. A compound which is 6-piperidino-2,10-dimethyl-4,8-di-tert-butyl-dibenz[d,g][1,3,6,2]dioxathiaphosphocine. 